The present invention relates generally to the art of support clips and brackets and, more particularly, to a box hanger and mounting clip assembly for securing an electrical box between two Tee bars or the like.
Heretofore, electrical junction boxes have been supported below grid ceilings using cumbersome support structures that are relatively difficult and costly to install. Prior methods of support involve, for example, the use of separate support members such as angle irons or unistruts which are cut to a required length at the job site. These support members are positioned on top of or above the grid ceiling at specified fixture support locations, and then they are anchored to the building superstructure by overhead load wires. Wherever an electrical feed is required, an electrical box must be installed along with the anchored support member. For this purpose, commercially available mounting rails or spanning bars that fasten to the Tee bars of the grid ceiling system are commonly used. Spanning bars are installed across the individual grids of the ceiling""s Tee bar grid structure and permit the electrical box to easily be located with selected grids. Sometimes a load wire is dropped directly to the spanning bar and attached by means of a wire clip, however, without independent support the load carrying capacity of such an arrangement is limited.
Acoustical xe2x80x9cTee Barxe2x80x9d electrical box hangers have been widely employed, in the construction of ceilings, and particularly suspended or drop ceilings. One example is the CADDY(copyright) 512 or 512A box hanger. CADDY(copyright) is a registered trademark of Erico, Inc. of Solon, Ohio. The hanger comprises two clips riveted to the ends of a spanning bar which snap on the bulb end of the stem of the Tee bar. The electrical box is held to the spanning bar by a spring finger clip embracing the bar which is secured to the back of the electrical box by a threaded fastener. To mount the clip to the box, a knock-out must be removed from the box. The spanning bar is rectangular and edgewise to the load, with the spring finger clip including a bent portion extending over the spanning bar and with a tab of the clip being inserted into the knock-out thereby engaging an inside surface of the back of the electrical box. The portion of the clip which is secured to the back of the electrical box by a threaded fastener requires lining up a threaded hole in the clip with a mating hole in the electrical box. The 512A hanger includes slotted intermediate brackets between the ends of the spanning bar and Tee bar clips. The spanning bar is secured to the brackets by threaded clamp fasteners.
As one skilled in the art can see, the above 512 box hanger assembly has a number of disadvantages. From the perspective of the installer, screws and other detached pieces of a multipart assembly can be discouraging. To install the 512 clip assembly to the electrical box, each and every piece of the entire assembly, with the tab of the clip inserted into the knock-out and the threaded hole lined up with the mating hole in the electrical box, must be carefully held together by the installer while the screw is installed through the box and into the clip. This method is very cumbersome and can be dangerous. One has to realize that this work is usually done on a ladder or scaffold and lost parts or forgotten special tools can be a real time wasting problem which can induce the installer into jury rigged unsafe shortcuts. Any slip of the bar or the assembly can result in the assembly losing its location in reference to the box. Moreover, all buildings vibrate, and suspended wire or chain drop ceilings are susceptible to special harmonics. A need therefore exists for a bar hanger and mounting clip assembly, having all the flexibility and advantages of the multipart 512 clip assembly, yet does not include the cumbersome disadvantages described above.
The present invention fulfills this need by providing a load bearing bar hanger and mounting clip assembly: that eliminates the need for the installer to carefully hold together each and every piece of the entire assembly, with the tab of the clip inserted into the knockout and the threaded hole lined up with the mating hole in the electrical box, while the screw fastener is installed through the box and into the clip; that eliminates the need for separate support structures; that can satisfy most load specifications; that offers a savings in labor and materials as compared to clip assemblies heretofore used; that can be installed using commercially available spanning bars; that can be installed relatively easily by providing a tension leg for temporarily holding the assembly in position on the electrical box as hardware is installed; that provides a means to center the point of attachment for a support wire to avoid cocked mounting of connected electrical devices; that substantially covers a knock-out opening of the electrical box to promote NEC compliance of the overall assembly; that is readily adapted for use at electrical feed locations; and that has added versatility so that it can be used to accommodate a wide variety of different structural environments and load wire configurations.
These objects and advantages are accomplished through a bar hanger and mounting clip assembly comprising a clip for securing an electrical box to a spanning bar, the clip comprising a first generally horizontally disposed flat portion engageable with an outer surface of the electrical box; an inverted generally U-shaped portion, attached to the first flat portion, sufficiently sized for receiving the spanning bar; a second generally horizontally disposed flat portion, attached to the inverted U-shaped portion, specifically configured to be received through a box knock-out opening formed in a wall of the electrical box, the second flat portion engaging an inner surface of the wall of the electrical box; and an initial holding means in the form of a tension leg for initially holding the clip in position on the electrical box before the clip is securely fastened to the electrical box. In this particular embodiment of the present invention, the tension leg comprises a first portion extending generally upwardly from the second flat portion of the clip; a second portion extending laterally outwardly and downwardly from the first portion of the tension leg; and a third portion extending generally upwardly from a lower edge of the second portion of the tension leg. The first, second and third portions of the tension leg and the second flat portion of the clip cooperate to form a channel means for receiving a peripheral edge of the knock-out opening in the wall of the electrical box. The distance of separation between the lower edge of the second portion of the tension leg and the second flat portion of the clip is preferably less than the thickness of the wall of the electrical box so that the lower edge resiliently engages the wall of the electrical box when the wall is received therein. The clip may further comprise a load wire attachment means for receiving and engaging one or more load wires. The load wire attachment means preferably comprises a generally upwardly extending wire attachment arm and at least one wire attachment hole formed in the arm for receiving one or more load wires. The wire attachment arm preferably extends generally upwardly from the inverted U-shaped portion of the clip. The clip substantially covers the knock-out opening in the electrical box once installed.
In another embodiment of the present invention, a bar hanger and mounting clip assembly for securing an electrical box between two opposed Tee bar elements in a ceiling structure is provided which comprises a spanning bar which spans between the two opposed Tee bar elements; first and second clips at opposed ends of the spanning bar for attaching the spanning bar to the two opposed Tee bar elements; an electrical box; and a mounting clip for securing the electrical box to the spanning bar, the mounting clip including initial holding means for initially holding the electrical box in position on the spanning bar before the clip is securely fastened to the electrical box. The mounting clip preferably comprises a first generally horizontally disposed flat portion engageable with an outer surface of the electrical box; an inverted generally U-shaped portion, attached to the first flat portion, sufficiently sized for receiving the spanning bar; and a second generally horizontally disposed flat portion, attached to the inverted U-shaped portion, specifically configured to be received through a box knock-out opening formed in a wall of the electrical box, the second flat portion engaging an inner surface of the wall of said electrical box. The initial holding means preferably comprises a tension leg which includes a first portion extending generally upwardly from the second flat portion of the mounting clip; a second portion extending laterally outwardly and downwardly from the first portion of the tension leg; and a third portion extending generally upwardly from a lower edge of the second portion of said tension leg. The first, second and third portions of the tension leg and the second flat portion of the mounting clip cooperate to form a channel means for receiving a peripheral edge of the knock-out opening in the wall of said electrical box. The distance of separation between the lower edge of the second portion of the tension leg and the second flat portion of the mounting clip is less than the thickness of the wall of the electrical box so that the lower edge resiliently engages the wall of the electrical box when the wall is received therein. The clip may further comprise a load wire attachment means for receiving and engaging one or more load wires which preferably comprises a generally upwardly extending wire attachment arm and at least one wire attachment hole formed in the arm for receiving the one or more load wires. The wire attachment arm preferably extends generally upwardly from the inverted U-shaped portion of the clip. The clip substantially covers the knock-out opening in the electrical box once installed.
Other objects, features, and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.